Habitat selection and preferred food plants of a desert‐dwelling elephant population in the northern Namib Desert, South West Africa/Namibia

Abstract

SUMMARY The habitat selection and woody food plant preferences of a desert‐dwelling elephant population in the extremely arid, northern Namib Desert region of South West Africa/Namibia are discussed. The river course habitat is clearly the best available habitat and also the only habitat upon which the elephants can depend for long‐term survival. Flood plains, however, seem to be the preferred habitat type, but are only available during the wet season. With the exception of the mountains and rocky plains, all the other habitat types are used on an opportunistic, short‐term basis only, while the gravel plains are mostly avoided. It is clear that the desert‐dwelling elephants have a definite preference for certain woody plant species, irrespective of plant availability or size. Colophospermum mopane Kirk ex Benth, Tamarix usneoides E. Meyer ex Bunge and Combretum imberbe Wanira appear to be the most important woody food plants in terms of forage bulk. The relatively opportunistic habitat selection and unspecialized nature of the diet of these elephants make them well suited to the adversities of their arid environment. Résumé On discute la sélection de l'habitat et les préférences pour les plantes alimentaires ligneuses chez une population d'éléphants nomades; cette population vit dans une région extrêmement aride au nord du désert de Namib, en Namibie. La végétation du bord des cours d'eau est manifestement le meilleur habitat disponible et le seul duquel dépend la survie à long terme des éléphants. Les plaines inondables semblent cependant être le type d'habitat préféré, mais qui n'est disponible que durant la saison des pluies. A l'exception des montagnes et des plaines rocheuses, tous les autres habitats sont exploités ponctuellement et de manière opportuniste. Les plaines de graviers sont expressément évitées. II est clair que ces éléphants nomades du désert ont une préférence marquée pour certaines espèces de plantes ligneuses, quelque soit la disponibilité de la plante ou sa taille. Colophospermum mopane, Tamarix usneoides, et Combretum imberbe semblent être les plantes ligneuses alimentaires les plus importantes comme base de fourrage. La sélection de l'habitat relativement opportuniste et la nature non spécialisée du régime alimentaire de ces éléphants les rendent préparés aux adversités de leur environnement aride.

Landscape-scale feeding patterns of African elephant inferred from carbon isotope analysis of feces

“…In such habitats, elephants cannot maintain dietary diversity by browsing in the dry season and, therefore, continue to graze even though the grass layer is diminished. This hypothesis seems to contradict earlier findings that mopane is an important resource for elephant (Viljoen 1989;Lewis 1991;Smallie and O'Connor 2000). Our results do not suggest that they do not browse in mopanedominated habitats of Kruger Park, merely that dietary diversity is a constraint.…”

Intraspecific Host Preferences of Mopane Moths (Imbrasia belina) in Mopane (Colophospermum mopane) Woodland

“…Variable foliar chemical composition is therefore also expected between habitat types (Kraus et al 2004). Furthermore, densities of mature mopane in woodland vary greatly, ranging from <10 trees/ha in arid northwestern Namibia (Viljoen 1989) to 481 trees/ha in southeastern Zimbabwe (Kelly & Walker 1976) and 2740 trees/ha in northern South Africa (this study). This high degree of variability within mopane woodlands thus results in very different habitat types for mopane moth larvae, which may in turn influence host preference by ovipositing female mopane moths at the habitat level.…”

Space and habitat use of the African elephant in the Tarangire–Manyara ecosystem, Tanzania: Implications for conservation

“…We further use our data to: (i) investigate the location and the availability of natural habitats of those areas outside the park that are of major importance during the wet season, (ii) determine and map the remaining migration routes still used by elephants, and (iii) apply data on elephant space use patterns and migration to suggest conservation strategies for the whole Tarangire-Manyara ecosystem. We consider 'migration' as a seasonal two-way movement, involving a return to the area originally vacated, usually following traditional pathways (Viljoen 1989). …”