Located c.100 km north of the town of Mkuze, Ndumo Game Reserve is situated on the Zululand coastal plain, with the altitude ranging from 22 to 120 m. It nestles at the eastern foot of the Lebombo mountains, at the junction of the Pongola and Usuthu flood-plain systems. The Pongola river runs through the reserve, from south to north, while the Usuthu river forms the northern border (which is also the international border with Mozambique). The topography is very flat, with a few small hills. There are two major semi-permanent flood-plain pans and many smaller permanent and ephemeral pans within the reserve.The flood-plain vegetation is characterized by abundant water-lilies Nymphaea, pondweed Potamogeton and papyrus Cyperus. Trees that form the adjacent riverine woodland strip include Acacia, Ficus and Syzygium. The tree communities occurring along seasonal stream banks include Spirostachys, Schotia and Acacia. Further away from the river, a deciduous tree and shrub community becomes dominant, although Acacia woodland dominates on the stony boulder outcrops. There is very little open grassland. In places, there are relict patches of well-developed sand forest, including trees of Sclerocarya, Albizia, Afzelia, Terminalia, Newtonia, Cladostemon and Balanites.
See Box and Tables 2 and 3 for key species. The rivers, flood-plains, pans, dams and vleis are important for many wetland birds, and species include Pelecanus onocrotalus, P. rufescens, Ciconia episcopus, Anastomus lamelligerus, Ephippiorhynchus senegalensis, Balearica regulorum, Phoenicopterus minor, Ardeola rufiventris, Gorsachius leuconotus, Microparra capensis> and Centropus grillii. The only recorded successful breeding of Anastomus lamelligerus in South Africa took place in Ndumo in 1972. The riverine forest holds Scotopelia peli and Podica senegalensis. This reserve is one of the few in KwaZulu-Natal that holds most of its original complement of raptors. The sand forest holds Nectarinia neergaardi (80–120 breeding pairs) and Hypargos margaritatus.
Non-bird biodiversity: Large mammals are well represented in Ndumo, including threatened species such as Ceratotherium simum (LR/cd) and Diceros bicornis (CR).
Pressure/threats to key biodiversity
The reserve was first proclaimed in 1939, and was for many years administered by the Natal Parks Board. In 1986 control passed to the KwaZulu Bureau for Natural Resources. With the subsequent amalgamation of that body with Natal Parks Board, the new organization—the KwaZulu-Natal Nature Conservation Service—runs the reserve. Veld management policies used to include the culling of large mammals and controlled burning.Poaching is regular, a function of the proximity of a national border. However, invasion by non-native plants, notably Chromolaena, Ricinus, Lantana, Psidium and Melia, is most serious. This became an issue after Cyclone Demoina, and is a recurring problem on the flood-plain. The Pongola is permanently infested with non-native water-hyacinth Eichhornia. Plans have been mooted to link Ndumo with the much larger Tembe Reserve to the east, by means of a corridor. This would greatly increase the viability of both areas.