Feeding Ecology of the Cuvier's Gazelle (Gazella cuvieri, Ogilby, 1841) in the Sahara Desert

Abstract

Knowledge of the feeding ecology of ungulates in arid biomes offers an interesting model for understanding the drought resistance of large desert-adapted herbivores, a crucial issue in the face of increasing desertification due to climate change. To assess the feeding ecology of the endangered Cuvier's gazelle (Gazella cuvieri) in the Sahara desert, we used a multi-method approach combining faecal samples, direct observations, and the recording of indirect signs of feeding. We hypothesised that browser behaviour is the best foraging strategy for species living in hyper-arid environments, mainly due to long periods without grazing opportunities. Complementarily, we explored the effects of the main environmental descriptors (rainfalls and NDVI) on feeding patterns and diet quality. We found that Cuvier's diets are based mainly on acacias (Vachellia tortilis, V. flava) and occasionally on the annual forb Anastatica hierochuntica. In total, eighteen species (five trees, nine shrubs, three herbs, and one grass) belonging to fifteen families were recorded. Our result confirmed the browsers' characteristic of this species, reaffirming its ability to settle in a hostile environment. Acacias stand out as key species consumed at the southernmost limit of their range; hence, future conservation plans and strategies should take this into account for the survival of Cuvier's gazelle in desert environments.

Keywords: Gazella cuvieri; Sahara; acacia; climatic change; deserts ecology; diet; wild ungulates; wildlife conservation.

Figure 1

Study area with sampling sites. Relief is represented by a raster digital elevation model (DEM) and is expressed by a colour gradient from darker (higher altitude) to lighter (lower altitude). The map also shows the main towns and distribution of Cuvier’s gazelle south of the Drâa River, considered its southernmost range [10,21].

Figure 2

Examples of Cuvier’s gazelle indirect feeding (IF) data obtained in the study area during the surveys: (A) Footprints recorded while one group was feeding on Vachellia tortilis. (B) Damage in Lavandula coronopifolia by browsing. (C) Calotropis procera consumed by a Cuvier’s gazelle. (D) Leaf of C. procera partially consumed by Cuvier’s gazelle.

Figure 3

(A) Contribution of plant species to the diet of Cuvier’s gazelles in the Sahara desert: from faecal samples (FSs) and indirect feeding (IF) data; * p < 0.001 of Chi² tests with Bonferroni’s correction. (B) Diet selection from IF; Ivlev’s electivity index (EI) is shown only for species with p < 0.0027 of Chi² tests with Bonferroni’s correction for acacias (Vachellia tortilis and V. flava) and Cymbopogon schoenanthus.

Figure 4

(A) Correlation panel showing Pearson’s coefficients between pairs of variables; positive relationships are represented in blue, negative ones in red. (B) Photo capture by camera-trapping of a male Cuvier’s gazelle feeding on Asparagus altissimus in the study area. (C) Bar plot representing the proportion of variance explained by the dimensions extracted from the PCA. (D) PCA results for relationships between the species consumed, Shannon’s index, diet quality, and selected environmental factors. Abbreviations: plants consumed: Ah (Anastatica hierochuntica), Nr (Nitraria retusa), Pd (Pennisetum divisum), Hl (Helianthemum lippii); Alt (Altitude), Annual temperature (Ann.t), Annual precipitation (Ann.Pp); NDVI: per year (Av.NDVI), weekly scales (Biweekly.NDVI), and seasonal (Season.NDVI); Shannon’s diversity index (Sannon.Ind). For all other abbreviations, see text.