Gazelle–livestock interactions 211


FIG. 6 Livestock encounter rate with respect to distance to hafiri, by season and year.


globally (see also Lafontaine et al., 2006), with no indication of persistent decline. Numbers in the study area were in- creasing during 2013–2019. It is not known whether this re- presents an increase in overall population size or increasing concentration because of environmental factors, and/or in- creased protection from activities related to the reintroduc- tion of the scimitar-horned oryx. We did not examine the status of the dorcas gazelle in the wider Reserve, but it is known that significant numbers are present. The species ranges widely across the whole Reserve and can survive for long periods independently of water (Yom-Tov et al., 1995; Scholte & Hashim, 2013a). For example, in September 2017, the population in the line transect survey zone was esti- mated to be 5,700 (95%CI 3,100–10,700), an apparent reduction of nearly 10,000 individuals relative to the estimate for the same zone 7 months earlier (Table 1). However, the mean encounter rate in the adjacent recon- naissance survey block to the north in September 2017 was four times higher than in the line transect zone, indicating a high likelihood thatmany individuals had moved 30–50 km north (Fig. 5). Large assemblies of dorcas gazelles were at that time attracted to extensive green pastures of Boerhavia sp., I. colutea and other green vegetation in the reconnaissance survey zone, while avoiding high


concentrations of livestock towards the east. Although dor- cas gazelle distribution was independent of artificial water sources, the species uses natural water sources that form temporarily after rainfall. In a localized study zone of the Negev desert, dorcas gazelles were associated with perman- ent water points (Henley et al., 2007). But free-living dorcas gazelles in Africa frequently experience prolonged absence of water, and routinely so in the 9-month dry season in Chad. The absence of association between dorcas gazelles and the array of artificial water points infers that habitat quality in the Reserve is still sufficient to allow dorcas ga- zelles to meet their water requirements across the seasonal cycle without having to rely on artificial water sources. Extensive coverage during the survey period confirmed


that dama gazelles are present in low numbers in a relatively restricted area. Nevertheless, previous research indicates this is the largest of the four remaining wild populations (Scholte & Hashim, 2013b; Mungall, 2018; IUCN/SSC, 2019). Data collected over two seasons suggests dama gazelles avoid live- stock in a similar way to dorcas gazelles, but may be even more sensitive to disturbance, commonly exhibiting much longer flight distances (often .500 m; SCF, unpubl. data, 2020). Evidence suggests that anthropogenic influences such as livestock presence, fire and occasional hunting by


Oryx, 2023, 57(2), 205–215 © The Author(s), 2022. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605321001629


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