habitat_narrative

Terrestrial

Acacia savannah/woodland and open woodland landscapes are the preferred habitats for this subspecies, especially where there are abundant woody trees. Giraffes in the Kalahari preferred tree densities of 744 to 1,084 plants / ha where they can select very specific woody species to browse (Deacon 2015). Theron (2005) found that, in the Free State, active browsing was responsible for 53% of the daily activities of the animals. During the day, browsing activities mostly took place in direct sunlight. Minimal time was spent in full or partial shade. During light rain showers, their ears were flattened and browsing continued undisturbed, but a hard rain shower usually caused a temporary cessation of browsing. Though individuals sometimes smelled the leaves of trees before browsing, especially in the Franklin Nature Reserve in South Africa with its unusual composition of potential feeding plants, no relation was found between wind and browsing direction (Theron 2005). The simultaneous browsing of the same plant by more than one Giraffe was observed regularly by most authors. In contrast to the assumption of Dagg (1960) and Spinage (1968) that feeding activity also dominated the night-time activities, browsing was responsible for less than a third (31%) of the total time budget during the night. In the early evening and the early morning hours, the browsing frequency was high (84%), but in the middle of the night it dropped to a low frequency (16%). In contrast, throughout the day, browsing took place at a relatively constant rate with an initial increase of 20% in the early morning and again in the late afternoon. Theron (2005) observed that mature bulls browsed significantly less than cows, supported by the findings of Du Toit (1990) and Pellew (1984). Young calves normally spend less time browsing, as mothers’ milk largely fulfils their nutritive requirements. Browsing represents the dominant activity of adult Giraffe in both the wet and dry seasons. In both sexes, browsing time increased slightly during periods of food scarcity.

Giraffes are exceptionally well-adapted to dry and arid habitats, with food availability during the dry season probably a fundamental regulator of Giraffe distribution (Berry & Bercovitch 2016). Although Acacia is often considered the limiting factor, such is not necessarily the case (Berry & Bercovitch 2016). One possible unfortunate consequence of this misperception is that many Giraffe translocations in South Africa are to places with Acacia trees, but Giraffes can cause substantial damage to the habitat when residing in small enclosed areas, especially to the Acacia trees (Bond & Loffell 2001; Parker & Bernard 2005; Deacon et al. 2012).

As with their diet, Giraffes in Africa demonstrate an enormous amount of variability in their home range size, but limited flexibility in their daily movement patterns. Home range size reflects resource availability and distribution, with dry season foods probably exerting a major impact on Giraffe ranging patterns and reproductive rates. McQualter et al. (2015) summarised results across Africa, reporting average home range sizes varying from about 10 km² to close to 500 km². In the Kalahari, the average home range (206 km², calculated from eight collared females; highest 438 km², lowest 65 km²) is larger than any average Giraffe home ranges previously reported (Deacon 2015): 25 km² in South Africa (Langman 1973), 68 km² in Zambia (Berry 1978) and 200 km² in Namibia (Fennessy 2009). Van der Jeugd and Prins (2000) reported mean home ranges of Giraffe in Lake Manyara National Park, Tanzania to be between 5 km² (males) and 9 km² (females), but with much variation: 0.1–22 km² (for males) and 0.5–27 km² (for females). Berry (1978) observed that average male home range (82 km²) was greater than female home range (68 km²), and the largest for a male was 145 km² in the Luangwa Valley, Zambia. Fennessy (2009) estimated one bull’s home range (in the Namib desert in northern Namibia) to be 1,950 km² and for one female 1,098 km². In the same study, the female’s mean annual home ranges varied from 200 km² to 220.7 km² (using the 100% minimum convex polygon) and from 24km² to 119 km² (using the 95% minimum convex polygon).

Ecosystem and cultural services: Giraffe are an iconic species of the African savannah. Giraffe are widely loved symbols of wildness and the beauty of nature.