The ecology of ungulates in the Waterberg Plateau National Park, Namibia.
Although ungulate species form an important component of Namibia’s economy through tourism, their population sizes vary substantially in relation to irregular rainfall, poaching, predation and competition, amongst other reasons. Understanding the ecology of ungulates is the key to adaptive ecosystem management and wildlife conservation in semi-arid savanna ecosystems. The study was conducted at Waterberg National Park, to determine habitat preferences, seasonal variation in population structure, daily drinking activities of twelve ungulate species and population dynamics of ungulates over a period of 33 years (1980-2013). The data used included road counts in all four vegetation types in the park (Terminalia sericea- Melhania acuminata vegetation, Terminalia sericea-Thesium megalocarpum, Terminalia sericea-Blepharis integrifolia, and the rock-inhabiting Peltophorum africanum community), waterhole counts, and pre-existing aerial counts. The probability of occurrence of large and medium ungulates was influenced by distance from the waterholes and from the roads. The population structure of seven herbivores varied in intricate ways between species and seasons. Smaller herds of ungulates were recorded most during the dry season as compared to larger herds observed during the wet season. Overall, the most frequent drinking times were between 15:00-22:00 with 18:00-19:00 being the conspicuous peak of the drinking activity, with 15% of animals in attendance. Four groups of ungulates were identified as per their drinking activity patterns: 1) day drinkers (warthog, giraffe, roan, and sable), 2) day/night drinkers (dik-dik, steenbok and common duiker), 3) evening/night drinkers (white rhino, black rhino and buffalo) and 4) night/morning drinkers (eland, gemsbok and kudu). The buffalo and eland population densities comprised together more than half of all ungulates recorded. Roan and sable antelope, kudu and warthog were also fairly common (with 5-12% of all ungulates recorded). White rhino, black rhino, giraffe, and gemsbok were classified as uncommon (together 11.9%), whilst the remaining seven species were rare (together 1.9%). Population size in eland showed a weak positive relationship with the annual average rainfall between the years 1981 - 2013, whereas population sizes in kudu, sable, gemsbok and roan showed a weak negative relationship with the amount of rain. No relationship was detected in giraffe, buffalo and hartebeest populations. The efficient management of wildlife resources that are economically and socially important necessitates regular surveys to monitor population trends in order to develop applicable management options. Thus, monitoring methods which are practical and efficient and provide accurate data are required for sound wildlife management. The results generated from this study provide novel contributions to strengthening management and conservation efforts of ungulates in Waterberg National Park and other wildlife parks in Namibia. More studies in the area of diet analysis of grazers and browsers as well as their preferences for particular plant species, with emphasis on inter- and intra- species competition is recommended.