Giraffe populations across the African continent have declined over the past decades, mainly due to habitat loss and fragmentation of subpopulations. To fight the decrease in numbers of the different giraffe species, conservation actions have been and are currently in place, such as translocations into protected areas and reintroductions into areas where giraffes have disappeared.
In Namibia, the Angolan subspecies is widely spread and mostly found on private land, which offers the opportunity to study the species in closed environments, therefore broadening the knowledge on how giraffes use their habitat in the wild. This information can subsequently be used to better manage giraffe populations in reserves and national parks and to gain a deeper understanding on which factors play a significant role in giraffes’ habitats.
This study focuses on the giraffe population of Kuzikus Wildlife Reserve, a private game reserve in the Kalahari region of Namibia. Field work was carried out from June to December 2021, covering the end of the dry season and the beginning of the rainy season. As no previous study on the local giraffe population had been carried out, there was no precise information on population numbers and structure. Therefore, it was determined how many individuals live in the reserve through individual pattern recognition. Furthermore, data on giraffe location, herd size and food source selection was collected. Additionally, a vegetation survey on browse availability and vegetation heterogeneity across the different vegetation types of the entire reserve was conducted. The goals of the research were to find out how the giraffes use the reserve and its resources and if there are differences between the two seasons.
The reserve’s population consisted of 41 individuals, and results showed they use the reserve differently when comparing the dry and rainy seasons. Overall, herd sizes were larger during the rainy season and giraffes fed on a wider variety of woody plants, as forage is more abundant and more plant species grow new foliage. Significant differences between females, males and calves were also found regarding food source selection. Acacia erioloba, was consumed for its abundance and availability throughout the year. On the other hand, Acacia karroo and Ziziphus mucronata, which are only green during the rainy season, were identified as preferred species. There was a shift of the giraffe distribution from the central area of the reserve to the northwest in the rainy season, corresponding to the location of the large limestone pans. During this season, they fill up with water and are surrounded by a diverse belt of bushes and trees. The pans and the dense bush areas were therefore significantly more used. When including information on vegetation in a spatial capture recapture
analysis, models showed population density variations were most dependent on browse availability and giraffe movement on seasonal shift. These findings match the results on home range estimates, which were not only generally larger for males but also during the dry season, as giraffes need to cover more distance every day to find sufficient food.
Kuzikus Wildlife Reserve, being a closed ecosystem with easily accessible areas and covered by different landscape types, offered an ideal opportunity to conduct this research. The Kalahari region of Namibia has not been widely studied regarding the species and knowing what giraffes need to thrive is essential for their protection and conservation. This new information will help the reserve’s owners make decisions on tourism, conservation and wildlife management and, more importantly, the knowledge can be transferred to other potential areas for giraffe reintroduction to find out if they collect the necessary characteristics to serve as a suitable habitat for the species.
